Question for controllers: I know you would rather be talking to VFR traffic than not. That aside, what goes on when VFR traffic calls for flight following? What information do you have to enter into the computer? How quickly do squawk codes get generated? Do squawk code numbers correlate to or mean anything or is it purely a random number? Just curious. Thanks!Ryan

I'm not a controller, but I am very familiar with the radar systems they use.

When you request flight following, the controller generates an abbreviated VFR flight plan for your callsign. This is not the same flight plan that you file with Flight Service.

There are two types of abbreviated flight plans: One is "local," and the other is "NAS," a national airspace system flight plan. In probably 90% of cases, the squawk code you get will tie your callsign to a local flight plan.

The computer entry for a local plan requires only a callsign. Aircraft type and destination can also be added. The entry is very simple: N1234 C172 JFK <enter>. The radar display nearly instantaneously shows a code that the controller tells you to squawk. When you squawk the code, the radar system "tags" you, or places your callsign and information the controller entered about you next to the target squawking your code.

There are several code blocks assigned to each facility, which are used for different purposes. From your last post, I know you fly near Portland, ME. The Portland TRACON is assigned the following code blocks:

0201-02300301-03300350-03770426-0453

Facility management decides what to do with each of those code blocks. Normally, it's (1) IFR, (2) VFR Flight Following, (3) VFR Practice Approach, and (4) other. I don't know the specifics of their code configuration, but those are what the facility has been assigned to use (FAA 7110.66D JE SUP 1).

There are basically three radar systems in use right now: Common ARTS, STARS, and HOST/DSR. Portland has ARTS-IIE, which is a Common ARTS system. They can pass local flight plans to other Common ARTS TRACONs, but only your callsign can be passed along. When you are switched to a neighboring approach control, Portland may say "Advise ABC Approach of your type aircraft and destination." Note that Common ARTS cannot pass along any local plan information to a STARS-based approach control, or a Center, which is based on HOST/DSR.

Controllers on Common ARTS have to go to a separate computer to enter you into a NAS abbreviated flight plan. This takes more time and is rarely done, but the benefit is that all of your information -- aircraft ID, type, and destination -- can be passed to any radar approach control or center.

Controllers using STARS will usually enter you into a local flight plan initially, but the STARS system permits controllers to change your local flight plan to a NAS flight plan with a simple keyboard entry. They'll normally do this in order to hand you off to a center or a Common ARTS-based approach control. Finally, if you begin flight following with a center, you are automatically entered into the NAS because their computer system only generates NAS flight plans.

From a center perspective, it's really easy to enter a VFR flight following. On our keyboards, we have a "code" button that we'll hit and then type in your callsign. A squawk number will appear. We tell you the squawk number and we wait to see it, a data block will pop up, we'll verify your altitude and then radar identify you. All we need is your aircraft type and destination. All we do is type in, "VP C172/A KPDK (3 digit ID or your callsign)" and done.

Most ATC facilities can input your info right from the scope. If they can accept an automated handoff from the overlying ARTCC, they should be able to put in the flight plan from the ARTS/STARS keyboard.

If you're talking to a center, they are already tied into the NAS and anything they put in will transfer to the next facility. If you're talking to an approach, what StuSEL said is pretty much right on, with one small catch...the callsign doesn't actually transfer to the next facility. The next approach control sees an asterisk and a beacon code with an altitude (they have to click on the target to get the code). For example, a target squawking 0244 at 3,200 feet would look like this (the groundspeed would probably appear as well when they 'slewed', or clicked on the target):

* 032 0244

The receiving controller wouldn't see a callsign until the controller working the airplane called on the landline with that information. Most of the time we give the type with the callsign, but that may not be SOP everywhere. Once the receiving controller has the callsign, they type it into the computer, click on the target, and it suddenly looks like:

A - N12345 032 12V

The 'A' being the position symbol for the receiving controller, 032 being 3,200 feet, 12 being 120 knots, and the V indicating the aircraft is VFR.

Well that's nice if your tower has an ARTS or STARS scope, however for those few of us that do not, a FDIO entry is all that is needed, for us it's callsign, type, requested altitude and destination, the rest we can make up.